Pantograph



March 12, 1935. G. MUZICZKA ETAL 1,994,401

PANTOGRAPH Original Filed May 2'7, 195].

AU/Inexes; Jwen/om:

Patented Mar. 122, i935 umrso stares:

rani- PANTQ GRAPH Georg Muziezka, Fischern, Czechoslovakia, and

Ernst Heinrich, Selle, Germany Appiication May 27,1931, Serial No.5%,328. Re-

newed October 25, 1934.

In Germany May 1 Claim. (01. 33-111 The present invention relates to apantograph comprising rules that can be joined together and serve forenlarging or reducing drawings and plans.

Ihe existing instruments for copying drawings, plans or the like to apredetermined scale suffer from serious drawbacks. Reducing rules, forinstance, can accommodate only two scales which must have the samesubdivision. .Polar pantonieters subject the eyes of the draftsman tosevere strain. The radial pantorneter produces a copy turned 180, theproduction of which requires much practice. adjustable reproducingreducing compasses and the pantograph have 'in common one importantadvantage, namely, the mechanical reproduction of the measures wanted,but this involves also the drawback of insumcient control ofmeasurements. Other defects of reducing compasses are the small range,insecure work at large, compass opening, easy variability of theclamping, and the spoiling or both the original and copy by piercing.Pantographs, on the other hand, are expensive, require a large andabsolutely plane drawing table, need much practice and are bothersome tostart and, owing to their bulk and weight, difficult to pack.

The invention eliminates these drawbacks by providing two independentrules which are fixed with their opposite zero points in a common point.

The instrument according to the invention is illustrated in theaccompanying drawing, in which Figure 1 is atop view thereof; Fig. 2, alongitudinal view thereof; and Fig. 3, a side View.

Referring 'to the drawing, A and B are the rules, the scales chosen forexample being 1: 1000 for A and 1:2500 for B. The rules A and B consistof strips of a material that is V as unchangeable as possible to insurepermanency of the divisions made thereon. To adhere closely to theirsupport, the strips are thin and elastic, while their width depends ontheir length but must be large enough to insure straightness of theedges. The strips may differ in length. The longer they are, the greaterwill be their range and the strain to which the means for holding themtogether is subjected. Each strip has. a difierent division extendingfrom left to right and arranged in corresponding position on both edges.

If the strips forming a set areof equal length, the strip for the largerdrawing will be used Proportionallyinstruments like the The joining ofthe strips is made possible by surrounding the zero points p of bothedges with circular projections 12, in the center of which, i. e., inthe zero point itself, apertures are provided for the pin 03. Each ofthe strips is formed with two of said circular projections 11 at one endthereof, one of said two projections being in the plane of the strip andthe other being ofiset in a plane parallel thereto to the extent of thethickness of the strip. This arrangement of the projections 0 permitscoupling of the two strips in the same plane.

Horizontal displacement is prevented by the pin d, which should offer aslittle resistance as possible, or a pin inserted in the drawing table.Vertical lifting of the coupling is prevented by the rubber ball piercedby the pin (1 and pressed down onto the coupling point.

The rules according to the invention? are very simple to use. After ithas been determined what ratio between the original and the reproductionis desired the corresponding pair of measuring strips A and B arechosen. It is determined whether the copy can be made from one point orgraticulation is necessary. In the latter case, the mark on'the stripfor the larger drawing indicates half the width of the squares for thelargest. possible graticule. The original is then placed on the tableand covered with transparent tracing paper for the reproduction. If agraticule has been prepared, the first cross of the graticule of thetracing paper is placed over the corresponding cross of the original sothat both are in perfect registery. Then the strips A and B are coupled,preferably by placing the original A below and B on top of it, so thatthe top edge of A and the lower edge of B 'are fixed. If a graticule hasbeen used, the zero points of these two edges are placed over the firstcross and fixed to the table exactly at the intersecting point by thepin d or a suitable other means whereupon the rubber bulbg is presseddown onto the coupling. Reproduction is effected by gauging a point oftheoriginal with A and reading the distance from the zero, whereupon Bis softly contacted with A which is then moved away instantly. Now thepreviously read distance is determined position of the A-edge, andtransferred to the reproduction. This process is repeated until thereproduction has been completed.

The device according to the invention permits working even within a verylimited space, protects the plans and ,the like by, dispensing withauxiliary lines or the like, can be easily handled without previousinstruction and requires only one-fifth to one-tenth of the time nowneeded to effect a reproduction. Furthermore, it insures absoluteprecision in reproducing a copy showing the same direction as theoriginal, permits an excellent control of the progress of the work andinstant checking of any errors I on B, the working edge of whichoccupies the

